Method and apparatus for electrical treatment of gases or liquids



Aug. 4, 1936. GRAVE 2,049,561 METHOD AND APPARATUS FOR ELECTRICAL TREATMENT OF GASES OR LIIQUIIIDS 'Fiied June 1; 1934 Currey) Jo urce Curr enf iaurre INVEN TOR. Georg 62 4 re fllfl k/ Patented Aug. 4, 1936 UNITED STATES PATENT OFFICE METHOD AND APPARATUS FOR ELECTBL CAL TREATMENT OF GASES OR LIQUIDS Georg Grave, Frankiort-on-the-ltiain, Germany,

assignor to International Precipitation Company, Los Angeles, Calif., a corporation of Calllornia Application June 1, 1934, Serial No. 728,621

In Germany June '7, 1933 a '1 Claims. (Cl. 183-7),

having relatively high resistance or dielectric.

properties, with high tension electric current or voltage, as for example in the electrical precipitation of suspended particles from gases or gas mixtures or in the electrical separation of emulsions. particularly in the dehydration of petroleum emulsions, it has been found advantageous in certain cases to subject the fluid medium (gas or liquid) in the electrical treatment chamber to successive treatments with diiferent types of elecf tric current, in order to increase the eiilciency of the treatment. In such cases, it has been found particularly advantageous to successively and periodically subject the fluid medium to the action of electric currents or voltages of widely differing characteristics, particularly with u'espect 2:, to the manner of variation of current-or voltage with respect to time. For example, it may be found advantageous to subject the fluid successively and separately to unidirectional current (including either continuous or intermittent direct 30. current or rectified alternating current), to alternating current, and to current applied in the form of intermittent sharp impulses of relatively short duration such as may be produced for example by the intermittent discharge of energy 35 from a condenser through a spark gap or the like.

The principal object of this invention, therefore, is to provide an increased efliciency of operation in the electrical treatment of fluids, by

40 successively and separately subjecting the fluid within a single treating chamber or apparatus to treatment with diflerent types of electric current or voltage, and particularly to treatment with types of electric current which differ from one 45 another in the manner of variation of current or voltage with respect to time. 1

A further object of the invention is to provide a simple apparatus for successively and separately applying the several different types of elec- 50 tric current or voltage to the electrode means of the electrical treating apparatus, such apparatus preferably comprising a plurality of contact mem bers connected to the plurality of sources of difierent types of electric current, and movable 65 switching means operable to successively and separately establish connection between the respective contact members and the electrode means oi the treating apparatus, at regular intervals.

The accompanying drawing illustrates apparatus embodying this invention, and referring 5 thereto: I v Figs. 1, 2 and 3 are diagrammatic representations of such apparatus; and

Fig. 4 is a graphic representation of different types of electric current which may be employed. 10 v In Figs. 1 and 2 an electrical treating apparatus is indicated'diagrammatically at l, consisting for example of anelectrical precipitator for removing suspended particles from gases or an electrical apparatus for separating emulsions. Said l5 apparatus is shown as comprising opposing electrode means 2 and 3 between which the fluid is passed and subjected to the action of the electric For example, .n

fleld between said electrodes. the case of electrical precipitation, the electrode 20 means 2 may constitute a discharge electrode member such as a wire or rod of small diameter, and the electrode means 3 may constitute a collecting electrode or electrodes of relatively extended surface, such as plates or pipes, in the usual manner of such apparatus.

I have shown three separate sources of electric current, indicated at A, B and C in Fig. 1 and at A, B and C in Fig. 2. Switching means I is provided for successively connecting said sources of current to the electrical treating apparatus, and said switching means maycomprise flxed contact members 4, 5 and 6 connected respectively to the current sources A, B and C or A,

B and C, and a rotating disc it formed of suitable insulating material and rotated at suitable speed in any desired manner, for example by means of an electric motor connected thereto in such manner as to provide the desired speed of rotation. Said disc is provided with two dia- 40.

metrically opposed contact members 8 and 9 at the periphery thereof, electrically connected as by conductor III to a contact ring it engaged by a brush I! which is connected by conductor l3 to one of'the opposing electrode means, such as electrode means 2, of thetreating apparatus.

In Fig. 1. A, B and C may represent sources of any desired diflerent types 01 electric current or voltage, and particularly, types or electric current which differ from one another in the manner of variation of current or voltage with respect to time. Said current, sources are, as

above stated, connected respectively at, one side to the fixed contact members I, 5 and}, and

are grounded at the other side as indicated at g;

l4, l5 and I 6, and the collecting electrodes 3 are also grounded as at l1 so as to complete the electric circuit through the respective current sources.

With disc I8 in the position shown, the rota ing contact member 8 is in efiective contacting relation (by spark contact) with the fixed contact 4, so that current will pass from A through said contacts and through contact ring H, brush l2 and conductor l3, to the electrode means 2, thus subjecting the fluid between the electrodes to the action of current from A. As the disc I8 is rotated in a clockwise direction, as indicated by the arrow, contact will be broken between contact members 8 and 4, and at this instant or shortly thereafter contact will be established between contact members 9 and 5, permitting current to flow from source B to the electrical treating apparatus. In the continued rotation of said disc, contact will be broken between contact members 9 and 5 and established between contact members 8 and 5, thus permitting current to flow from source C to the treating apparatus.

Thus, the respective current sources A, B and C are successively connected, at regular intervals and for definite periods of time, to the electrode means of the treating apparatus, and the fluid therein is successively subjected to the different types of electric current. It will be understood that the gaseous or liquid fluid to be subjected to treatment is continually passed through the treating apparatus I and between the electrode means 2 and 3. The disc 18 may be rotated at any suitable speed so as to provide any desired duration of treatment with each type of electric current, and, if desired, the contact members 4, 5 and 6 may be made of different lengths, so as to provide difierent durations of treatment with the respective types of current. Also,-by varying the angular extent of the fixed and rotating contact members, the duration of contact with each current source may be varied so that, if desired, intervals of no current supply may be provided between the periods of connection to the several current sources.

In the specific example shown in Fig. 2, A represents a source of alternating current, such as transformer 2|. One side of the secondary winding of said transformer is connected to contact member 4 and the other side is grounded as at I4. B is shown as a source of unidirectional current and, more particularly, of rectified alternating current, comprising a transformer 22 and a rectifier 23 of any suitable type, such as a mechanical, thermionic, or copper oxide rectifier. The input terminals of said rectifier are connected to'the secondary winding of transformer 22, while the output or rectified current terminals thereof are connected respectively to contact member 5 and to ground as indicated at l5.

C represents a source of unidirectional current of the intermittent impulse type. comprising, for example, a transformer 24, a suitable high voltage rectifier 25, condenser 26 and spark gap 21. One of the rectified current terminals of rectifier 25 is connected through impedance means 28 (consisting of inductance or resistance or both) to condenser 26 and spark gap 21, while the other of said terminals is grounded as indicated at 29. The other side of condenser 25 is also grounded as at 30, while the other side of spark gap 21 is connected to the fixed contact member 6. In the operation of this form of cur-' rent supply means, the unidirectional energy from rectifier 25 is stored in condenser 26 until said condenser is charged to a suificient voltage to cause a breakdown to occur at spark gap 21, whereupon the stored energy is delivered from the condenser through said spark gap. This energy is therefore discharged in the form of a sharp unidirectional impulse of extremely steep wave front and short duration. Due to the sudden discharge of energy from condenser 26, the voltage falls until the spark is extinguished at gap 21, and the operation is then repeated, thus providing a series of sharp impulses with relatively long intervals therebetween. Since condenser 25 is charged by means of unidirectional current, it is apparent that the intermittent discharges occasioned by the breakdown of gap 21 will also be essentially unidirectional; however, I may in some cases omit the rectifier 25 and charge said condenser by means of alternating current, in which case intermittent discharges of alternating or opposite polarities may be obtained. The function of the impedance means 28 is to prevent high frequency oscillations resulting from the sudden discharges occurring in the circuit including the condenser and spark gap, from reaching the current supply means including transformer 24 and rectifier 25. It will be understood that the above mentioned intermittent dischargestake place only during those periods in which the fixed contact member 6 is in effective contact with one of the rotating contact members 8 or 9 and that, during the intervals between these periods of contact, the circuit will operate only to charge condenser 26 to the full voltage delivered by the transformer and rectifier.

The operation of the system shown in Fig. 2 is similar to that shown in Fig. 1, the electrode means 2 and 3 being periodically and successively energized by means of alternating current from source A, rectified alternating current from source B, and intermittent unidirectional impulse current from source C. The wave forms of the voltage, for these three different types of electric current, are illustrated graphically in Fig. 3, in which time is plotted horizontally and voltage vertically. The horizontal lines 0-0 represent zero voltage; the sine wave curve indicated at a represents the alternating voltage delivered by current source A; the curve b represents the rectified voltage delivered by current source 3', the solid portions b' of this curve indicating the portions of the peaks of the successive half-waves which are picked off and delivered to the fixed contact member 5 in case the rectifier 23 is of the ordinary type of mechanical rectifying apparatus such as commonly employed in connection with electrical precipitation of suspended particles from gases; and the curve 0 represents the voltage produced by the impulse type current source C, in which the voltage rises sharply at the time of each discharge of the condenser 25,'as indicated at c, and then falls to a relatively low value, providing a succession of intermittent high potential impulses of steep wave front and sharp peak. The alternating and rectified voltages a and b may be of'any desired frequency and, in the case of the intermittent impulse voltage, the constants of the circuit may be so adjusted as to provide any desired interval between the successive impulses 0'. Furthermore, the speed of rotation of the distributing disc l8 may be such as to provide for any desired duration of contact with the respective fied half waves, or intermittent sharp impulses aoeaaei such as shown at may be delivered to the electrode means of the treating apparatus i during each of these periods.

In Fig. 3 I have shown an electrical treating apparatus, such as an electrical precipitator or an electrical de-emulsifying apparatus, comprising three electrical treating units or sections indi- "cated at M, 32 and 33, each comprising opposing ductors 35, 36 and 31, to the electrode means 2 of the respective treating units 3|, 32 and 33. The rotating contact members 8 and 9 of the respective switches la, lb and 1c are offset 60 from oneanother, in such manner that the respective current sources are, at any given time, electrically connected to the electrode means of different treating units. Thus, in the position shown, current source A is connected by its distributing switch la to the electrode means 2 of the treating unit 3|, current source B is connected through its distributing switch lb to the electrode means 2 of treating unit 33, while current source C is connected by its distributing switch 'lc to the electrode means 2 of treating unit 32, and the several switches act to simultaneously shift the connections between the several current sources and the several treating units, so that each current source is successively connected to the respective treating units at different times. revolution of the distributing switches serves to successively connect each current source successively to the several treating units, it will be seen that this apparatus provides for a more eflicient utilization of the several current sources and also enables a plurality of electrical treating units to be energized from one source of each type of electric current employed. The distributing switches la, lb and 1c may be driven in any suitable manner, and I have diagrammatically indicated all of these switches as being mounted upon a common shaft 34 which may be rotated at any desired speed. The fluid to be treated may be passed either in series or in parallel between the electrode means of the respective treating units at, 32 and 33, or difierent fluids may be passed through said units for treatment therein.

1 claim:

1. An apparatus for electric treatment of fluids comprising: a plurality of electrical treating units each provided with opposing electrode means and with means for passing fluid between said electrode means; a plurality of sources of different types of electric current, the types of electric .current produced by the respective current sources difi ering from one another in the manner of variation of current or voltage withrespect to time; and switching means operable to successively and separately connect each of said Since each half current sources to the electrode means of each of said treating units, at regular intervals.

2. An apparatus for electrical treatment of fluids comprising an electrical treating apparatus provided with opposing electrode means, a plurality of sources of different types of electric current including a source of intermittent sharp impulse current providing a succession of short unidirectional high potential impulses of steep wave front and sharp peak, and switching means operable to connect successively and separately each of said current sources to said electrode means at regular intervals.

3. An apparatus for electrical treatment of fluids comprising an electrical treating apparatus provided with opposing electrode means, a plurality of sources of different types of electric current including a source of intermittent sharp impulse current providing a succession of short high potential impulses of steep wave front and sharp peak, and a source of unidirectional current, and switching means operable to connect successively and separately each of said current sources to said electrode means at regular intervals.

4. An apparatus for electrical treatment of fluids comprising an electrical treating apparatus provided with opposing electrode means, a plurality of sources of different types of electric current including a source of intermittent sharp 1 impulse current providing a succession of short high potential impulses of steep wave front and sharp peak, and a source of alternating current, and switching means operable to connect successively and separately each of said current sources to said electrode means at regular inter vals.

5. A method for electrical treatment of fluids comprising passing a fluid to be treated between opposing electrode means, and successively supplying to said electrode means at regular intervals a plurality of types of electric current including intermittent sharp impulse current supplied as a succession of short unidirectional high potential impulses of steep wave front and sharp peak.

6. A method for electrical treatment of fluids comprising passing a fluid to be treated between opposing electrode means, and successively supplying to -said electrode means at regular intervals a plurality of types of electric current including intermittent sharp impulse current and unidirectional current, said intermittent sharp impulse currentcomprising a succession of short high potentialiimpulses of steep wave front and sharp peak. I

'7. A method fo electrical treatment of fluids comprising'passing a fluid to be treated between opposing electrode means, and successively supplying to said electrode means at regular intervals a plurality of types of electric current including intermittent sharp impulse current and sharp peak.

GEORG GRAVE. 

